Nafi’ reported: Uthman, may Allah be pleased with him, saw the Prophet, peace and blessings be upon him, in his dream on the night he was killed the following morning. The Prophet said, “O Uthman, break your fast with us tonight.” Then, he was killed while he was fasting.
Source: Dalā’il al-Nubuwwah lil-Bayhaqī 7/48
Grade: Thiqah (reliable) according to Ibn Hajar
عَنْ نَافِعٍ أَنَّ عُثْمَانَ رَضِيَ اللهُ عَنْهُ رَأَى النَّبِيَّ صَلَّى اللهُ عَلَيْهِ وَسَلَّمَ فِي مَنَامِهِ فِي اللَّيْلَةِ الَّتِي قُتِلَ فِي صَبِيحَتِهَا فَقَالَ يَا عُثْمَانُ أَفْطِرْ عِنْدَنَا اللَّيْلَةَ فَقُتِلَ وَهُوَ صَائِمٌ
7/48 دلائل النبوة للبيهقي
5/21 المحدث ابن حجر العسقلاني خلاصة حكم المحدث رجاله ثقات في المطالب العالية